Aldehydes of the saturated and unsaturated pregnane series



Patented Mar. 17, 1942 ALD-EHYDES on THE SATURATED AND UNSATURATED PREGNANE scams Kart Micscher, Riehen, Switzerland, Werner- Fischer and Caesar Scholz, Summit, N. .12, and Albert Wettstein, Basel, Switzerland, assignors to Ciba Pharmaceutical Products,Incorporated,

Summit, N. J.

No Drawing. Original application June 27, 1939,

Serial No, 281,488. Divided and this application. March 25, 1941, Serial No. 385,208. In

Switzerland July 1, 1938 (C1, Wo -1397.54

4;" Claims.

This invention relates. to. the. manufacture of. aldehydes of; the saturated and unsaturatedpre none-series in which the aldehyde group is. in 2 position. The method of manufactur may be one that is in itself known (compare for example: Chemi der Kohlenstoffverbindungen, 12th edition, vol. 1, page 245 and following, and J.

Houben: Die Methoden der Organischen Chem-ie, 3rd edition, vol. 3, page 529. and follow ing) s parent materials may be used for example compounds of the saturated and unsaturated pregnane-series which contain an oxyag roup in Zl-DQSifi-QII or a reactive: ester of such compound.

These compounds. are subjected; to an oxidizing.

process whereby an aldehyde group is formed in 2l-position. The usual oxidizing agents have proved advantageous in this case (compare J. Houben, loc. cit. vol}. 2:, page 22 and following and 47 and following), also the exchange of oxidation stages with carbonyl com-uounds. in presence ofmetal alcoholates as Well as: biochemical oxidation. A further oxidizing proces consists in starting from a reactive ester of a 21-oxy-com-. pound for example a 2 .-halog.en or a 2l-toluene sulphonic acid ester compound and: converting. this in a manner in itself known, for example by way of the hexamethylene-tetramine-comnound- (compare Sommelet: Comptes rendus', 157', 852 [19MB into the corresponding aldehyde, The last named process is particularly suitable in the case where the parent material is a Z-I-halogen derivative with an active hydro en atom in .21;-

position, for instance in the case of A -u-n saturated 2l-halogen derivatives or in the case of a. 2:0-keto-2Lhalogen derivative. Further free carbinol groups which may be nresent may be converted if desired the cour e of such an oxidation process also into carbonyl groups. If a simultaneous oxidation or dehydrogenation of such carbinol groups or other oxidizable groupings is not desired, these groups or groupings may be protected for instance. by este fiflqation or etherification. Parent materials having secondary carbinol groups protected by esterification and free primary carbinol groups in Zfi-positionare accessible by reaction of the free polyoxycompound with a triaryl-methyl halide to term a 2l-mono-ether, action of an acylating agent whereby an ether-ester is obtained and eliminating the 21-ether group for example by means of an acid or reducing agent. Also double linkings which may be present may be protected intermediately if desired in the known manner. In, stead of a 21-oxy-compound the parent material may be a. ZI-acid derivative of the saturated and unsaturated pregnane-series, for instance a carboxyliic acid halide or anhydride, a carboxylic acid salt, imido halide, a diarylamid'ine or the like and this may be treated with a reducing agent whereby a. 21-aldehyde is also produced (compare. J. Houben, loc. cit.,vo1. 2, page 287 and following). In the course of this reaction also an ethylene oxide group present in 17:20- position may be reduced with formation of a hydroxyl group.

A further method consists in eliminating the side chain double linkingin 21-unsaturated derivatives of this series, for exampleby an oxidation. This may be doneby ozonizing and splitting the ozonide, by action of a peroxide preferably in presence of osmium tetroxide, or by addingtwo, hydroxyl groups at the double linking andby scission of the glycol thus produced (compare J. Houben, loc. cit. vol. 2, page 127 and following and' 153 and following). If desired nuclear double linkings may thereby be temporarily protected as also may be further oxidizablegroupings. In the case of a carbon-nitrogendouble linking the splitting may be effectedhydro-lytically.

The parent material may be substituted in the; nucleus as well as. in. the side chain in any desired manner and may be of any desired steric configuration. In particular one may start even from 17:20-unsaturated compounds or from" compounds which in this 17:20-position contains an oxido group or one or two free or substituted ydroxyl groups, for instance acyloXy-, alkoxyor halogen-groups or a methylene group or ketogroup in 20-position. At any desired period of time the reaction a, free or esterified hydroxyl group being present. in l'I-position may be eliminated in the form of water or an acid. Moreover a free or substituted hydroxyl group may be introduced in a manner in itself known in LZ- p@Sj.t3iOn to the new aldehyde group and the, compound thus obtained may be treated with a, re-esterifying hydrolyzing and/0r esterifying or etheritying agent. Added to this one may attack the compound, for instance with halogen and if desired substitute for the halogen in the a-halogen derivative thus obtained a free or substituted hydroxyl group by aid of a hydrolyzing or re,- esterifying agent. The same oal may be obtained, however, by adding oxygen to the aldehyde enol derivative of the parent material, for example an enol ester, enol ether or enamine and; treating the ethylene oxide compound thus obtained with a hydrolyzing agent or by sat- Example 1 1 part of 3-acetoxy-androstane-17-acetic acid chloride (made for example from A A pregnadiene-3-ol-21-acid of melting point 21'7- 218" C. by hydrogenation, acetylation and treatment with thionyl chloride; the parent acid may be made from trans-dehydro-androsterone-acetate by reaction with bromacetic acid ester, elimination of water and saponification) is reduced by hydrogen, with aid of 1 part of palladium barium sulphate catalyst, in 30 parts of dry xylene at a bath temperature of about 150 C. When the reaction is complete the whole is filtered. The filtrate is evaporated and the residue purified by recrystallization, chromatographing or by conversion into carbonyl derivative. The B-acetoxy-pregnane-Zl-al is thus obtained in the form of colourless crystals.

Alternatively to reduce the acid chloride the corresponding calcium salt may be heated with calcium formate.

If instead of the above compound a corresponding 17:20-oxido-compound is used as parent material the oxygen bridge is reduced in the course of the reaction.

' To a solution of 3.6 parts of the above described 3-acetoxy-pregnane-21-a1 in 100 parts of glacial acetic acid there is added a drop of a solution of hydrogen bromide in glacial acetic acid and quite gradually there is allowed to flow in a solution of 1.6 parts of bromine in 50 parts of glacial acetic acid. The mixture is then poured into 1000 parts of water and the whole is extracted with ether. Th ethereal solution is washed with much water and evaporated. The residue is esterified by boiling for 1 hour with a solution of 3 parts of potassium acetate in 100 parts of absolute alcohol, the mass is again poured into water and the whole extracted with ether and the etherea1 solution washed with much water. On evaporation of the ether there is left a residue through which after chromatographic purification there may be obtained by recrystallization from hexane or dilute acetone the 3:20- dlacetoxy-pregnane-21-al.

By cautiou saponification with aqueous alcoholic potassium carbonate solution the pregnane- 3220-diol-21-al is obtained.

Instead of the pregnane-derivative one may start from the corresponding allo-pregnane-compound.

Example 2 room temperature until the hydrogen peroxide has been consumed. To the Weakly acid liquid is now added 0.1 part of barium carbonate-and the liquid is concentrated in a vacuum and taken up in alcohol in order that inorganic substances may be separated by filtration. The solvent is then evaporated from the filtrate, the residue is mixed with a little water and extracted by means of methylene-chloride to dissolve A -pregnene- 17:20-diol-3-one-21-al. By evaporating the solvent and purifying by crystallization, sublimation, adsorption or by way of a derivative, for instance phenylhydrazone or semi-carbazone, the new compound is isolated.

Advantageously instead of from free pregnene-triol-one one may start from its 20-monoor l'lzzo-diacyl-compound. They may be made for example from A -pregnene-17:20:21-triol- 3-one-21-monotritylether by cautiously or strongly acylating and subsequently eliminating the 21- ether residue by means of an acid agent. By using as parent material the corresponding isomeric triol of melting point 189-190 C. (made for example from A, A -pregnadiene-3-one- 21-01 by treatment with osmium tetroxide) the corresponding isomeric 21-aldehyde may be obtained in an analogous manner.

Example 3 1 part of A -21-bromo-pregnene-3-one (made for example from A -l'l-ethenyl-androstene- 3:1'7-diol, acylated with propionic acid anhydride to A -l'l-ethenyl-androstene-B:17-diol 3 propionate, transposition by means of acetic anhydride to A A -pregnadiene-3:21-diol-3- propionate-Zl-acetate, partial saponification, hydrogenation and bromination to A -21-bromo pregnene-3-ol-propionate, sa-ponification and oxidation of the free 3-OH-group) is heated together with 0.5 part of hexamethylenetetramine in .20 parts of aqueous alcohol for 3 hours under reflux. The greater part of the solvent is then evaporated in a vacuum and. from the residue the A -pregnene-3-one-21-al is isolated, for example by way of its condensation product with a ketone reagent, by chromatographing, sublimation and recrystallization from dilute methanol.

3 parts of this A -pregnene-3-one-21-al are converted by boiling for 6 hours with 60 parts of acetic anhydride and 3 parts of anhydrous sodium acetate into its 21-enolacetate. The latter is precipitated by means of water and extracted by ether and the ethereal solution treated with an ethereal solution of 1.5 parts of perbenzoic acid. The small excess of acid is now withdrawn with N-sodium carbonate solution and the ethereal solution is washed further with water, dried and evaporated. The residue is heated with alcoholic hydrochloric caid to hydrolize the u-OXldB. Finally aqueous potassium carbonate solution is added for the purpose of completely saponifying the enol-ester-group and the solution is poured into water and extracted with ether; the ethereal solution is washed with water, dried and evaporated. The residue purified by chromatographing is crystallized from dilute acetone in the form of colourless needles which are A -pregnene-3-one-20- ol-2 1-al. This body may be converted for instance by action of an acid anhydride or chloride in pyridine at room temperature into its ester, for instance acetate, propionate or benzoate.

In an analogous manner one can obtain instead of enol-esters, enol-ethers or enamines which may be again split up by means of acid.

The present application is a division of applicants prior application Serial No. 281,488, filed June 27, 1939. 1

What we claim is: sisting of saturated and unsaturated 'pregnanel. A compound selected from the class con- 3-one-20-ol- 2l-als. sisting of saturated and unsaturated pregnane- 4. The A -pregnene-3-one-20o1-21-a1s. 20-o1-21-a1s.

2. A compound selected from the class con- 5 KARLMIESCHER. sisting of saturated and unsaturated pregnane- WERNER FISCHER. 3:20-di01-21-a1s. CAESAR SCHOLZ.

3. A compound selected from the class 0011- ALBERT WETTSTEIN. 

